1. Field of the Invention
This invention relates to facings for use with plastic foamed construction insulation boards. These boards are used primarily in roofs and walls, and they serve to insulate the interior of buildings from heat and cold.
2. Description of the Prior Art
Facings for plastic foamed construction insulation board are located on one or both sides of a central plastic foamed core and during manufacture of the boards support liquids which are used to create the plastic foam. In order to provide a good bond between the facing and the board, it is desirable that the liquid flow partially into the facing, but it is also important that no foam-forming liquid flow through or "bleed" through the facing during manufacturing, inasmuch as that tends to contaminate the manufacturing machinery with plastic.
Between manufacture and installation, and after installation, facings provide strength and durability to resist moisture and other damage, which can result in loss of insulating properties. In many uses these boards must resist substantial stresses such as may result from the lifting effect of wind when the boards are installed on roofing. The facing material should provide strength to the boards to resist such forces.
Facings used with insulation boards of the plastic foamed type have included metal foils sometimes reinforced with scrim, as shown in U.S. Pat. No. 4,073,998 issued to P.M. O'Connor, and mats of glass fibers as exemplified by U.S. Pat. Nos. 4,388,366 and 4,414,265, issued to D.W. Rosato. Facing materials may also include expanded pearlite boards, metal foils, organic felt, heavy papers saturated with 100% or more of their weight in asphalt, plywood, hard board, cement-asbestos board, reinforced plastic, tempered glass and glass fiber board. Paper alone has not been used for this purpose probably because one would expect (i) foam-forming liquids to bleed through paper during manufacture of the board, (ii) moisture to seep through the paper after manufacture, which could cause delamination, (iii) paper to be dangerously flammable, and (iv) paper's lack of dimensional stability to cause warped boards.